This person came in after a high speed motor vehicle collision. Their main complaint was neck pain near C-7:
As you can see under bone windows there is a fracture of C7. One could stop here and be satisfied that you see the primary pathology in which you were interested. However, anytime you look at a CT you should pay attention to all parts of the image. Secondary findings are very common, especially in trauma. When assessing a CT image, one should change windows on the image to adequately look at all types of tissue that are present. In a cervical spine CT, the top of the lungs are usually visualized in the catchment area as you get to the upper t-spine. If you change the window to “lung” windows this is what you’ll see:
This person also has an anterior, small pneumothorax! This could have easily been missed if not changing the window to look at the lungs.
One of the basics of CT imaging is to change windows for all types of tissue. In the head, your main window change will be from “brain” to “bone” to adequately visualize bony structures of the calavarium. In the abdomen you should switch to “lungs” to visualize the lungs as well as switch to “bone” to visualize the ribs, pelvis, and spine. There are many other examples of this principle, but we will leave it at this for now.
Author: Russell Jones, MD